<p>question: <a href=“http://talk.collegeconfidential.com/sat-preparation/1157673-sat-psat-prep-different.html[/url]”>http://talk.collegeconfidential.com/sat-preparation/1157673-sat-psat-prep-different.html</a></p>
<p>I legit thought that was undefined???!?!
wasn’t it?</p>
<p>Jackfrost,</p>
<p>The question stated that there ARE 3 lines and 3 planes. It then went on to say that two on the planes intersect at one of the lines. Then it asked you which of the three possibilities COULD possibly happen. I put down two of the possibilities, the one i didn’t put is that the third plane is parallel to both the first two planes.</p>
<p>@jubilee no reason for a restriction. ln(sinx)=0 ln1=0 therefore sinx=1 x=inv.sin1, which is within its domain</p>
<p>Tis exam seemed very theory heavy.</p>
<p>you can’t even graph that…
type in y = ln(sinx) into a graphing calculator</p>
<p>and you can’t have a y that = 0!</p>
<p>@llazar — I got III only, the one that said one of the planes was parallel to one of the other planes.</p>
<p>^^ that’s true, but in III, if it would be parallel to only one line, that would only make 2 lines of intersection between the three planes</p>
<p>For the ln(sin x) question…i was very frustrated.</p>
<p>ln(sin x) = 0 means that e^0 = sin x</p>
<p>So i thought ok, e^0 = 1, and sin x = 1 when x = 90</p>
<p>I think it asked for the value of ln(x). I plugged in ln(90) and got 4.5…not even close to any of the options. So i put undefined.</p>
<p>yea exactly… thats what I put!</p>
<p>II and III for that big fraction? Anyone get that?</p>
<p>we need the exact wording on 50 to determine the answer. the graph doesnt show it, but in notation ln x=y is e^y=x so e^0=1 because any number to the power of 0 is 1</p>
<p>What I thought was ln(1)=0 and sin(pi/2)=1, so I did ln(pi/2)</p>
<p>The question asked for all the things that COULD be true, they didn’t necessarily need to all be true at once. So, if two planes intersect along one line, then another plane can exist such that it intersects the two other planes at two distinct points. This was one of the options, and i’m fairly sure it is possible.</p>
<p>III was also possible, so was correct. There were 2 possibilities, though these possibilities don’t necessarily need to both occur, again because the test asked what COULD be true.</p>
<p>III only for big fraction</p>
<p>thats because you did it in degrees. The answers were in radians.</p>
<p>Chord one was 9.4, right? It made sense using law of cosine</p>
<p>Any idea what omit 8, -4 will be?</p>
<p>at ilazar: I hope that’s it, cause I put that, but now it seems like it’s pushing it a little. cross my fingers!</p>
<p>Were there any other choices with 9? I was really rushed on that problem, picked A fwiw</p>
<p>^Probably ~740</p>